Simplex Trading Portfolio holdings
Simplex Trading, founded in 2004 and headquartered in Chicago, Illinois, is a technology-driven proprietary trading firm specializing in market-making and liquidity provision, primarily in U.S. equity options and futures options. Leveraging advanced proprietary software and data-driven analysis, the firm optimizes trading strategies and develops innovative solutions to capitalize on financial market opportunities, maintaining a competitive edge through automation and a collaborative team of technologists and traders. With a workforce exceeding 300 and led by CEO Erik Swanson since 2014, Simplex operates with a low-ego, high-intelligence culture, focusing on minimal bureaucracy and rapid execution, while also making strategic venture capital investments in fintech startups. Recognized as a top workplace in Chicago by Built In’s 2025 awards, Simplex continues to evolve, blending cutting-edge technology with a commitment to market efficiency and growth.
Top Buys
| Rank | Stock | Value |
|---|---|---|
| 1 |
Netflix
NFLX
|
+$73.1M |
| 2 |
Western Digital
WDC
|
+$51.8M |
| 3 |
iShares Semiconductor ETF
SOXX
|
+$46M |
| 4 |
Meta Platforms (Facebook)
META
|
+$41.8M |
| 5 |
Alibaba
BABA
|
+$37.1M |
Top Sells
| Rank | Stock | Value |
|---|---|---|
| 1 |
NVIDIA
NVDA
|
+$262M |
| 2 |
Microsoft
MSFT
|
+$194M |
| 3 |
iShares Russell 2000 ETF
IWM
|
+$149M |
| 4 |
Apple
AAPL
|
+$119M |
| 5 |
Amazon
AMZN
|
+$107M |
Sector Composition
| Rank | Sector | Weight |
|---|---|---|
| 1 | Technology | 0.59% |
| 2 | Consumer Discretionary | 0.21% |
| 3 | Healthcare | 0.2% |
| 4 | Industrials | 0.18% |
| 5 | Communication Services | 0.16% |
| Name | Market Value | Portfolio Weight | Shares or Principal |
Change in Stake | Capital Flow | |
|---|---|---|---|---|---|---|
4876
CALL
Perimeter Solutions
PRM
$4.91B
| $113K | ﹤0.01% |
4,100
-6,000
| -59% | -$152K |
|
|
GAU
4877
CALL
Galiano Gold
GAU
$444M
| $113K | ﹤0.01% |
44,600
+35,100
| +369% | +$86.8K |
|
4878
CALL
Leslie's
LESL
$8.42M
| $113K | ﹤0.01% |
68,200
-13,700
| -17% | -$44.4K |
|
4879
PUT
Outset Medical
OM
$85.8M
| $112K | ﹤0.01% |
30,300
+28,800
| +1,920% | +$247K |
|
|
CRCG
4880
CALL
Leverage Shares 2X Long CRCL Daily ETF
CRCG
$77.3M
| $112K | ﹤0.01% |
4,090
+3,390
| +484% | +$185K |
|
|
OTLY
4881
PUT
Oatly Group
OTLY
$451M
| $112K | ﹤0.01% |
51,400
-6,700
| -12% | -$88.8K |
|
4882
PUT
CG Oncology
CGON
$6.19B
| $112K | ﹤0.01% |
2,700
+1,600
| +145% | +$66.2K |
|
|
TDAY
4883
CALL
USA Today Co
TDAY
$1.27B
| $112K | ﹤0.01% |
21,700
+14,600
| +206% | +$68.6K |
|
4884
Nomad Foods
NOMD
$1.71B
| $112K | ﹤0.01% |
8,933
-3,608
| -29% | -$44K |
|
4885
CALL
POSCO
PKX
$16.1B
| $112K | ﹤0.01% |
2,100
| – | – |
|
|
SY
4886
So-Young International
SY
$197M
| $112K | ﹤0.01% |
43,639
+15,501
| +55% | +$50.3K |
|
4887
PUT
Cohu
COHU
$2.32B
| $112K | ﹤0.01% |
4,800
+3,300
| +220% | +$75.6K |
|
4888
Glaukos
GKOS
$9.91B
| $111K | ﹤0.01% |
986
-353
| -26% | -$33.7K |
|
4889
BRC Group Holdings
RILY
$287M
| $111K | ﹤0.01% |
23,824
-136,012
| -85% | -$673K |
|
4890
CALL
VinFast Auto
VFS
$7.3B
| $111K | ﹤0.01% |
33,300
+17,700
| +113% | +$59.1K |
|
4891
PUT
Disc Medicine
IRON
$2.97B
| $111K | ﹤0.01% |
1,400
-400
| -22% | -$33.8K |
|
4892
PUT
United Natural Foods
UNFI
$2.98B
| $111K | ﹤0.01% |
3,300
-55,500
| -94% | -$2.06M |
|
4893
PUT
F&G Annuities & Life
FG
$3.88B
| $111K | ﹤0.01% |
3,600
-100
| -3% | -$3.13K |
|
4894
CALL
Universal Corp
UVV
$1.32B
| $111K | ﹤0.01% |
2,100
-1,800
| -46% | -$95.6K |
|
4895
CALL
LivaNova
LIVN
$4.45B
| $111K | ﹤0.01% |
1,800
-200
| -10% | -$11.4K |
|
4896
PUT
Inspire Medical Systems
INSP
$1.43B
| $111K | ﹤0.01% |
1,200
+200
| +20% | +$19.1K |
|
|
NUVL
4897
PUT
DELISTED
Nuvalent
NUVL
| $111K | ﹤0.01% |
1,100
+600
| +120% | +$59.2K |
|
4898
PUT
Telus
TU
$14.6B
| $111K | ﹤0.01% |
+8,400
| New | +$118K |
|
|
AGNT
4899
PUT
AGNT Inc
AGNT
$657M
| $110K | ﹤0.01% |
12,200
+3,700
| +44% | +$39.1K |
|
4900
PUT
Pricesmart
PSMT
$5.96B
| $110K | ﹤0.01% |
900
| – | – |
|
Similar funds
Simplex Trading's Q4 2025 Portfolio in Review
As of Q4 2025, Simplex Trading held 10,526 positions worth $177B, down 9% from $195B the previous quarter. Its ten largest holdings account for 49% of the portfolio.
Simplex Trading withdrew a net $23.2B in Q4 2025, closing 2,184 positions and reducing 4,088 holdings. Its most notable exit was iShares Russell 2000 ETF, an estimated $149M position sold in full.
By sector, the portfolio is most concentrated in Technology at 0.59% of assets, down from 0.79% a quarter earlier, followed by Consumer Discretionary and Healthcare.
Against the trend, Simplex Trading opened a new position in Western Digital worth $58.9M.
- Simplex Trading's largest Q4 2025 buy was Western Digital: 341,762 shares worth $58.9M.
- Simplex Trading added most to Netflix in Q4 2025, an estimated $73.1M increase.
- Simplex Trading's biggest Q4 2025 reduction was NVIDIA, cutting an estimated $262M.
- Simplex Trading fully exited iShares Russell 2000 ETF in Q4 2025, selling an estimated $149M.
- Simplex Trading's ten largest holdings make up 49% of its $177B portfolio in Q4 2025.
- Simplex Trading opened 1,476 new positions and closed 2,184 in Q4 2025.
- Simplex Trading's portfolio value fell 9% quarter-over-quarter to $177B.
Based on Simplex Trading's 13F filing for Q4 2025, filed 11 Feb 2026.